RELATIONSHIP BETWEEN WOOD DENSITY AND ANATOMY WITH DRILLING RESISTANCE BY NON-DESTRUCTIVE EVALUATION METHOD

The Resistograph has emerged as efficient non-destructive evaluation method, because it allows the fast assessment of mechanical resistance, density and other wood properties. The aim of the present study is to assess the influence of wood density and anatomy on resistance to resistographi drilling. Twenty trees of Eucalyptus grandis x Eucalyptus urophylla hybrids, at the age group of 6 years, whose chest height discs (CHD) were removed and subjected to diametrical strip drilling, were herein assessed. The critical locations of amplitude radius were selected after the visual analysis of the resistogram; it was done to remove samples for the anatomical analysis and density carried out to determine several moisture contents. Resistance to drill increased due to increased wood density. Person’s correlation between resistance to drill and basic density reached 0.67; density in hygroscopic moisture was 0.65. There was moderate correlation between fiber wall amplitude and thickness (r=0.65). Cell wall thickness, fiber length and lumen diameter were the main anatomical features contributing to higher resistance to resistograph drilling.